This invention relates generally to audio systems, and more particularly to a device for automatically attenuating an audio system when a coupled telephone is used.
Since it is difficult, if not impossible, to carry-on a telephone conversation while an adjacent audio system is playing at a moderate to loud volume level, the instant invention provides a convenient means for either manually or automatically decreasing the volume of the audio system while a telephone is being used.
Prior art, audio attenuating devices come in a wide variety of designs. Generally speaking, these devices can be broken down into two categories of devices, namely, mechanically actuated and electronically actuated devices.
Mechanically actuated devices generally employ a switching means which opens or closes a circuit for decreasing (attenuating) audio coincidental with the telephone user's picking up the telephone handset. One such device is disclosed in U. S. Pat. No. 3,532,823 (Ellis). The Ellis device utilizes a fairly simple switch means for actuating the attenuation circuitry. In that regard, in that Ellis device when the telephone handset is picked up from the telephone, the telephone handset is disengaged from contact with a switch lever, permitting the switch to move to an open position which in turn actuates to attenuation circuitry, thereby decreasing the audio output level of the audio system.
Many of the other mechanically actuated devices are far more complex than the one disclosed by Ellis. For instance, U. S. Pat. No. 2,792,450 (Hof) discloses and claims an automatic telephone cut-off switch which utilizes a complicated base structure upon which the telephone rests. This base structure is essentially a type of balance or weighing scale which is calibrated to the weight of the particular telephone resting thereon. Thus, when the handset portion is removed from the telephone, the base portion responds to the decrease in weight, causing a switching mechanism attached thereto to actuate the attenuation circuitry of the device.
As should be apparent, devices such as these which utilize mechanical switching means tend to alter the general apperance of the telephone by necessitating the use of accessory members which are to be attached to, or lie adjacent the telephone. Furthermore, as is generally the case with devices employing mechanical switching means, these devices are subject to the possibility of mechanical switching failures which would cause the device to malfunction.
An electronically actuated device which operates to attenuate an audio system conincidental with the ringing of a telephone is disclosed in U.S. Pat. No. 3,445,976 (Shaw). The Shaw device which is electronically coupled to the ring-producing circuitry of the telephone, overcomes the above mentioned disadvantages inherent in mechanically actuated attenuating devices. However, the Shaw device has certain other limitation which greatly diminish its utility.
One limitation of the Shaw device is that once the telephone conversation has been completed, the attenuating means must be manually disengaged in order to restore the volume of the audio system to its normal level. It should be quite obvious that the advantage of using a device designed to afford one the convenience of not having to manually turn down the volume of an audio system prior to conducting a telephone conversation would be greatly diminished by a device requiring the user of the device to manually disengage its operation following the completion of the telephone conversation. Moreover, in being coupled to the ring-producing circuitry of the telephone, the Shaw device's automatic attenuating capability is totally inoperative in situations where the one using the device is the one initiating the telephone call.
With regard to the attenuation means for actually decreasing the audio output, many of the prior art devices utilize circuitry which either completely turns off the audio of the audio system or alternatively, is connected to the audio system in a manner which entails the modification of the amplification circuitry of the audio system. For instance, in the Shaw patent the attenuating means is connected directly to the audio system's amplifier circuitry. Thus, the Shaw device requires actual modification of the audio circuitry, clearly dependent upon the specific equipment in use. Moreover, the nature and scope of the modification is not generally known and may not readily be implemented by an average user. As a result, there is the inherent possibility that the normal performance of the audio system will be affected by the device.
Likewise, the devices which completely disengage the audio system are also considered undesirable since many people do not want to completely turn the audio off during a telephone conversation but merely wish to decrease its volume.
Other devices for attenuating or cutting off audio of a connected audio system in response to use of a telephone are disclosed in the following U.S. Pat. Nos. 2,498,349 (Van Velsor); 1,775,567 (Lewis); 2,212,792 (Reading); and 2,503,095 (Butler).